Closing device for organism culture vessels



y 31, 1 G. KAPSEN BERG CLOSING DEVICE FOR ORGANISM CULTURE VESSELS Filed Sept. 26, 1931 jkvenzor: e'ralrlws A ilfo n Z277 Patented May 31, 1932,

earner oer GERARDUVS KAPSEN'IBERG, or GRONINGEN; NETHERLANDS CLOSING- DEVICE FOR ORGANISM CULTURE VESSELS Applicationfiledseptember 26, 1931, Serial No 565,384, and. in the Netherlands September 23, 1930. 1

In bacteriology tubes, flasks and similar vessels containing a substratum prepared for inoculatin with bacteria moulds or other livingorganisms, or having been inoculated with said organisms, the separation from the surrounding atmosphere is effected by a plug of wadding. This plug is not an airtight closing but keeps away germs from the air (bacteria, spores of moulds etc.) in a sulficient though not absolute manner.

It maybe remarkedand this is important with regard to the hereafter described closing device-that Louis Pasteur kept sterile liquids in flasks in sterile condition by-draw- 5 ing out the neck of said flasks to a capillary tube and bending this capillary tube. Consequently a wadding plug is not inevitably required, but of course it is much easierto apply a wadding plug than to draw out the neck of a tube or flask. I p

The use of a wadding plug, however, has several drawbacks,

(1) The making of a good wadding plug requires time and skill,

(2) If the culture tube closed by the plug is sterilized in dry condition and the dry sterilizatoris heated too high, for instance to 200 (1, which may easily occur, the plug becomes brittle and powdery.

In the operation of inoculating and reinoculating this is undesirable because powder of cotton wool falls in the substratum and the closing is effected less easily and is less efiiciente (3) In the filling of the culture tubes with substratum, care must be taken that this does not touch the upper inner side of the tube, because the plug of wedding is applied there and if the substratum is touched by the plug the consequences are:

( a) The wadding plug imbibes some of the material of the substratum so that moulds may easily grow in the plug with the result that infection of the substratum follows soon. (6) The plug will stick to the tube; it is diflicult to remove; it loses its proper form; and some of the fibres remain sticking to the inner side of the tube, all these causes prevent a sterile inoculation'and reinoculation.

(4) In the wet sterilizing method (most generally practised) it occurs that during cooling condensed water reaches the wadding plug, moistens thisplug and reaches the substratum which is diluted by it. In a busy trade such a fault is difiicult to prevent. Also it may be that the substratum foams and the foam reaches the lower part of the wedding plug. Then again the plug becomes a feeding base for moulds. I

(5) When, as usual, a large number of culture tubes, provided with a substratum, are made and kept in store, two difficulties may occur:

(a) The feeding bottom desiccates, by evaporation of water.

(b) In course of time bacteria or moulds grow or fall through the wedding plug.

Concerning desiccation this may be pre vented by several artifices, such as providing alayer of paraflin wax or by the use of capsules. These artifices, however, often present difliculties.

The growing of bacteria and moulds through the plug is not prevented thereby.

(6) When inoculating and reinoculating, the drawbacks of the wedding plug become evident. The removal of the plug and holding it between thefingers requiressome skill. It is inevitable that even skilled. persons sometimes let the plug slip out of their hands. In the flashing operation the plug often takes fire. When the cultures are reinoculated the wedding plugs always give some dust, which is especially detrimental when many cultures have to be reinoculated shortly after each other. If the plug sticks to the upper end of the tube (in consequence of the presenceof part of the substratum there) reinoculating is diflicult. If theinoculations have to be taken many times from, the same tube the plug loses its form, and it becomes more and more diflicult to introduce it into the tube. If bacteria grow slowly, such as the tubercle bacillus, desiccation must be prevented. The required artifices are cumbersome and not alwa s sufficient.

7) The wadding plu s are generally used only once. This is an economical disadvanotwithstanding the drawbacks of the use of a wadding plug, its use is maintained by its real qualities: simplicity, generally suf-- ficient germfree closing, and easy handling.

A device combining the qualities of the wadding plug but without its drawbacks is not easily found. Several attempts have been made but were not successful. A device which may be substituted with success for the wadding plug willhave to fulfill the following requirements: i r (a) It must fit well to the ordinary culture tubes now generally in use,

(b) It must fit firmly in these tubes,

0) It must not require extra room, (I) It must be sterilizable,

2e It must not be breakable,

f It must provide agermtight closing,

(9) It should be as easy to handle as a wedding plug or possibly easier,

(h) It should not be expensive.

All the substitutes proposed until now for the wadding plug have been unsuccessful. The closing by a reverted glass tube does not come up to the requirements I), e and 9.

Such glass caps slip easily from the tubes, are very breakable and not so easy to handle as a wadding plug. A glass cap is also used for closing the special culture tubes, mentioned in the German Patent 454,87 6. They have the same drawbacks.

The cap described in German Patent 508,597 does not come up to the requirements a, c, and g. This cap fits only specially made tubes or bottles. These must be provided with reversed edges and preferably below with a projecting ring. Between the edge and this ring a ring of asbestos is provided. The cap according to this patent cannot be used in ordinary bacteriologic or microbiologic research.

In order to solve the problem of substituting for the ordinary wadding plug a device which completely, and under all conditions of microbiological work, takes its place and at the same time avoids its drawbacks, I have proceeded on the idea that the device should have the same qualities as the wadding plug, but have these qualities in another and better form.

The closing cap according to the invention is composed of three parts (1) A rod or handle which may be provided with a knob,

(2) A bell-shaped cap,

(3) A little spring inside the cap.

The little rod is a handle and therefore a substitute for the part of the wadding plug extending from the culture tube. It is evident that a rod may be kept much easier and with more certainty between the fingers than a loose mass of cotton wool.

The bell-shaped cap closes germtight. Between the upper edge of the culture tube and the upper edge of the cap, between the outside of the culture tube and the inner side of the cap, between the part projecting from the centre of the cap towards the inner side of the culture tube and said tube, always remains a narrow capillary air space. .This is not passed by bacteria because the same conditionsprevail here as in the capillary tubes used by Pasteur and as in the spaces between the fibres of a wadding plug. The same causes, which make Pasteurs capillary tube and a wadding plug germtight closings, also prevent bacteria from passing between the cap and the culture tube. It has been shown by experiments that the cap as described is even abetter germtight closing than a good wadding plug. Yet there is a sufiicient diffusion of air so that bacteria grow very well, at least as well as with the use of a wadding plug. The sterilization takes place without any difficulty because the closing is not hermetic.

The cap does not take more space than an ordinary wadding plug, considering that the projecting part of the wadding plug also projects over the edge of the culture tube.

Resuming the aforesaid it may be said that 7 the cap represents the germtight closing inherent to the wadding plug.

The spring represents the clenching action of the plug. It fixes the cap firmly on the culture tubes without taking outward space. The cap is held more firmly by the spring in the culture tube than the wadding plug is held by its elasticity; one may take up the culture tube by the cap without any inconvenlence.

The spring is an important part of the cap. It is not so easy to find its correct form. With the spring the cap has become a reliable closing, more reliable than a wadding plug which often gets loose in the culture tube.

The spring is preferably made in such manner that it also enters intot-he tubes, having an inner diameter somewhat larger or smaller than the mean. The culture tubes most commonly used have an outer diameter very near to 18 mm. The thickness of the glass, however, is more or less variable.

For a better understanding of the invention, one construction of the cap according to the invention will now be described with reference to the accompanying drawings.

In these drawings,

Fig. I is a longitudinal section of the cap between the two clips of the spring.

lO-Ii lit) bit)

Fig. II is a longitudinal section of the cap at right angles tothe section of Fig. I.

Fig. III is a View from 'below'of the positionofFig'I. fu Fig.1V is a View through'the culture tube with its capsule.

In these figures, the reference characters are appliedas follows 7 (a) The knob of the handle, 7 (b) The rod of the handle, 1 (c) The bell-shaped cap, I 'rZ) The clenching device by which th spring device is attached to the inn-er upper sidev of the cap,

(e) A spring device containing two clips 7 forming one piece,

. (f)'-A circular groove between the disc like member (Z and the side wall of the cap,

(g) Aculture tube. The bending of the clips of the spring is such thatthe width of thecurve. is greater than the inner diameter of the tube, and if the cap is-removed froin the tube the spring will generally press against the side wall of the cap.

The mean exterior diameter of the most usual culturetubes is somewhat below 18 mm, and the inner diameter of the closing cap for such culture tubes is about 18 mm.

It must be understood that the details given are intended in no way to limit the invention which may be varied in many ways without departing from the spirit of the invention.

The advantages of the described closing device with respect to the wadding plug and othermeans for closing culture tubes and the like can be explained in the best manner with respect to the requirements given above (1) A closing by means of a wadding plug or the like, for instance a plug of paperstuii, must be made always anew. This requires much time and some skill. It is often done incorrectly. Closing caps are always ready for use; it requires hardly any time to apply one and this may be done by unskilled persons.

(2) In the preparation of the wadding plugs dust is likely. to be formed by which i germs of bacteria and moulds may be distributed in the room and may infect substrata. This dust is also disagreeable. The closing caps form no dust.

(3) The closing cap is fixed firmly on the culture tube, more firmly than a wadding plug, and of course, much more firmly than a cap without a'spring. When removing and storing the tubes the closing caps remain in their place; with wadding plugs this is not always so, and with caps without a spring nearly never occurs.

(4) The culture tube may be lifted up lifting the closing cap. Generally tl is is not possible with a wadding plug and also undesirable. This advantage is important if,

as often occurs, a culture tube has to be removed froin a tank in which there are many of them. Withtubes provided with a closingcap with a handle, this is very simple; it is rather dificult with tubes closed by a wadding plug or a cap without a handle. (5) A closing cap is not altered by sterilization, even if the temperature in the sterilizator becomes too high. The wadding plug on the contrary is always damaged by sterilization especially ifthe temperature is too high.

(6) The closing cap may be sterilized sepa rately which is not the case with a wadding p s (7) If in the filling operation some ma terial of the substratum has come into contact with the upper inner side of the culture tubes this is practically without any drawback if a closing cap is used. It will not. stick to the small surface of contact and there will not be any growth of moulds. Under the same conditions the wadding plug sticks to the tubes and moulds are easily developed.

(8) Foaming of the substratum: and Howing in of condensed water are not to be feared if a closing cap is used. The use of closing caps makes it even possible to pile up the usual wire baskets with culture tubes'in wet sterilization process. When wadding plugs are used extra precautions must be taken. I

(9) The closing cap prevents to a large extent desiccation of the substratum. Comparative experiments with tubes closed by a normal wadding plug have shown this in a surprisin degree.

(10) (lomplete shutting off from the air for cultivating purposes is efiected easily and cleanly by the application ofadhesiveplaster, a layer of plasticine or the like.

(11) The construction of the closing caps prevents the growing of moulds through the closing; substrate. provided with a closing capsule according to the invention remain practically sterile for an indefinite period.

(12) Inoculation and reinoculation are effected much more easily than when using a wadding plug. The handling of the rod and keeping it between the fingers is a very simple manipulation. The troublesome ignition of the Wadding plug (and sometimes of all the plugs on a standard) is prevented with the use of closingcaps though they are easily sterilized by the application of a flame. The cap retains always its form and therefore can be replaced very easily on the culture tube after inoculation. All thiscauses the inoculation and reinoculation to be effected much more easily, faster and in a more reliable and pleasant way with the use of a closing cap than with the use of a wadding plug.

(13) The wadding plug is generally used only. once. The closing cap may be sterilized many times and always used anew.

more value than 100 wadding plugs, but probably much more. \Vhen manufactured to a large scale the cap is a wholesale article.

The cap according to the drawings is fit for the most commonly used culture tubes. For culture tubes with a smaller or larger diameter, culture flasks and culture bottles, the dimensions of the cap must be varied accordingly. The construction remains substantially the same.

A suitable material for the cap is aluminium, covered with a suitable coating such as bakalite. The springs are preferably made ofrust-proof steel, but also other materials may be used.

What I claim is 1. Closing device for culture vessels, such as culture tubes and flasks for microbiological research work, comprising a bell-shaped cap, and a spring device within said cap for fixing the cap on the vessel.

2. Closing device for culture vessels, such as culture tubes and flasks for microbiological research work, comprising a bell-shaped cap having an inner diameter slightly greater than the outer diameter of the part of the vessel on which it is applied, and a spring device within said cap to fix the cap on the vessel.

3. Closing device for culture vessels, such as culture tubes and flasks for microbiological research work, comprising a bell-shaped cap having an inner diameter slightly greater than the outer diameter of the part of the vessel on which it is applied, and a spring device within said cap attached to the inner top side of the cap and projecting downwards so as to fix the cap on the vessel.

4. Closing device according to claim 1, in which the cap is provided with a rod-shaped handle.

7 5. Closing device according to claim 2, in which the cap is provided with a rod-shaped handle.

6. Closing device according to claim 3, in which the top of the cap is provided with a rod having a knob.

7. Closing device for culture vessels, such as culture tubes and flasks for microbiological research work, comprising a cap having an inner diameter slightly greater than the outer diameter of the mouth of the tube or flask on which it is to be applied, and a spring device within said cap attached to the inner top side of the cap and extending downwards with two arms, each arm consisting of a curved resilient wire, the width of the curve being somewhat larger than the inner diameter of the tube or flask on which the cap is applied. I

8. Closing device accordin to claim 7, having a rod fixed on the top of t e cap.

9. Closing device for culture vessels, such as culture tubes and flasks for microbiological research work, comprising a cap having an inner diameter slightly greater than the outer diameter of the mouth of the vessel on which it is applied, a spring device within said cap attached to the inner top side of the cap by a disc like member centrally connected with the cap, said spring device consisting of two curved arms of resilient wire extending downwards in the cap, the width of the cuwe corresponding substantially with the inner diameter of the cap, and a rodshaped handle fixed on the top of the cap.

10. Closing device according to claim 9, in which the rod-shaped handle is provided with a knob.

11. Closing device according to claim 9, in which the two arms of the spring are formed of one piece of wire.

In testimony whereof, I affix my signature.

GERARDUS KAPSENBERG. 

